High beam issue

[Stuntmonkey]

Hola!

So my high beams aren't coming on. Indicator light is, low beams and DRL work. Fuses are fine, bulbs are fine, both filaments are fine.

I'm being lead to the dimmer relay? It doesn't click when I switch it to high and low. I don't have a schematic for it so haven't got a clue which 4 prongs on the fuse I should be testing for resistance.

Any ideas?

 

[Stuntmonkey]

Jumpered the prongs in the fuse that had resistance, low beams come on. Jumpered other 2, and voila! High beams. New fuse I guess.

 

[Stuntmonkey]

So picked up a new dimmer relay, freaking $85. No high beams still!!

I understand its a switched ground, but in the indicator light is coming on, I can't figure out what the issue is?

High beams work AT the fuse when jumpered, so I guess I need to work my way back to the stalk?

 

[TheDurk]

So picked up a new dimmer relay, freaking $85. No high beams still!!

I understand its a switched ground, but in the indicator light is coming on, I can't figure out what the issue is?

High beams work AT the fuse when jumpered, so I guess I need to work my way back to the stalk?

I'd bet it's the stalk itself. Note that the indicator light is actually a LOW BEAM NOT ON light, It took me a while to figure that out but it's true. When the stalk goes to low, it creates a shunt to ground AROUND the high beam indicator, turning it off. The circuit is completely separate from the actual headlight high beam circuit except the power source. Assuming you have non-DRL setup (the switched ground setup), here is the schematic:

EDIT: Now that I think about it, there is no dimmer relay on the non-DRL. That means you have switched hots and DRL's, right?

Here is that schematic, too.

 

[Stuntmonkey]

I have DRLs, but did not know that about the light. Makes sense though. Which is why it comes on. I'll try and source a stalk if its not expensive.

I've been trying to find the pin out so that I can jumper the plug at the stalk to see if they come on, but haven't had any luck.

 

[TheDurk]

I have DRLs, but did not know that about the light. Makes sense though. Which is why it comes on. I'll try and source a stalk if its not expensive.

I've been trying to find the pin out so that I can jumper the plug at the stalk to see if they come on, but haven't had any luck.

Yeah, that circuit is a whole lot more complex. I'm not sure if the indicator light works the same way. I can get you the pin out. Hang on.

EDIT: Here it is--C13 on this diagram. The numbers correspond to the wires on the schematic. Jump 16 to 7 and if highs come on your stalk is toast. On the DRL setup, you do need to confirm the location of the fail as there are a lot more parts involved.

In the future, you can access these diagrams here: http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/local%20files/wiring.html

 

[Stuntmonkey]

Jumped 16/7 and the low beams came on with the high beam indicator light. So whatever part of the high beam circuit that puts them on isn't coming on for some reason. Both filaments light up for high beams.

UGH, this is a massive headache. I drive back home through the country roads and high beams are a necessity.

 

[TheDurk]

Jumped 16/7 and the low beams came on with the high beam indicator light. So whatever part of the high beam circuit that puts them on isn't coming on for some reason. Both filaments light up for high beams.

UGH, this is a massive headache. I drive back home through the country roads and high beams are a necessity.

No, both filaments do not light up for high beams on these trucks. We have the same headlights, and my fogs are tapped at the low wire so they only come on at low beam. I doubt it's different on DRL trucks. That's what the schematic says, too, if I read it correctly.

You said you changed the dimmer relay. Is terminal 2 of the dimmer relay switching on and off as you go from high to low? That is, is the relay coil receiving signal?

 

[Stuntmonkey]

Yup terminal 2 is getting 9v while on and then 0v when off. Tested this with lights on and off on the stalk, and then flashing high beams while lights were off.

What does the HEAD fuse control? Is that just the overall power to the headlights?

 

[TheDurk]

So picked up a new dimmer relay, freaking $85. No high beams still!!

I understand its a switched ground, but in the indicator light is coming on, I can't figure out what the issue is?

High beams work AT the fuse when jumpered, so I guess I need to work my way back to the stalk?

Please explain exactly what that means, and is it still true? Are you sure those fuses didn't blow again? Because if you have power at the fuses, there is only a straight shot to the bulb. Can you confirm that you have ground at the common terminal at the bulb when set to HIGH?

I don't see any HEAD fuse in the circuit other than the four for the headlights.

 

[Stuntmonkey]

Please explain exactly what that means, and is it still true? Are you sure those fuses didn't blow again? Because if you have power at the fuses, there is only a straight shot to the bulb. Can you confirm that you have ground at the common terminal at the bulb when set to HIGH?

I don't see any HEAD fuse in the circuit other than the four for the headlights.

If I jumper 1 and 2 on the fuse block, with my highbeams on at the stalk, they come on. This is why I originally thought it was the fuse.

Dimmer is the one I've been playing with, I was just curious to the HEAD down the bottom right.

 

[TheDurk]

That's not a FUSE, that's a relay. It controls main power to the headlights based on a signal from the stalk. It connects to Pin 4 on the dimmer relay. Not your problem, since lows work.

You mean they (the highs) come on if you jump around the fuse? If so, you were right, the fuses were blown. As I said, check those fuses again and see if there is power before and after the fuse--use a test light with one end on ground.

 

[Stuntmonkey]

Just to add to the confusion, I disconnected the DRL because it was annoying me. When I pull the stalk back to flash high beams with lights off, the lows come on.

And I believe I must have a different pin out than those ones you provided, looking at my stalk connector, I have nothing in pin # 17, and when #7 and #8 are bridged the lows come on, as opposed to #16 and #17.

:wtf:

The only thing I removed or changed from the truck since the high beams stopped working was adding my blue seas fuse block, which shares the batteries chassis ground, and took out a bunch of old alarm crap that was no longer in use and had, maybe 3 wires connected to it.

Thanks for you help so far Durk, I appreciate it.

 

[TheDurk]

Just to add to the confusion, I disconnected the DRL because it was annoying me. When I pull the stalk back to flash high beams with lights off, the lows come on.

And I believe I must have a different pin out than those ones you provided, looking at my stalk connector, I have nothing in pin # 17, and when #7 and #8 are bridged the lows come on, as opposed to #16 and #17.

:wtf:

[Uhh, there is no #17 on the circuit I gave you, either. Bridging #7 and #8 should be the FLASH. Test this by bridging with headlights off. If lows come on, it was flash, but the dimmer circuit isn't working, which we know. If they stay dark, only then it was the lows.]
The only thing I removed or changed from the truck since the high beams stopped working was adding my blue seas fuse block, which shares the batteries chassis ground, and took out a bunch of old alarm crap that was no longer in use and had, maybe 3 wires connected to it.

Thanks for you help so far Durk, I appreciate it.

Yeah, I don't have DRL's. Now that you mention it, I recall there are some differences among the years. What year do you have?

I would start at the bulb again and trace backwards with HiGHs turned on. Confirm ground at the common, then go check for 12V+ at HIGH bulb terminal, then HIGH HEAD R/L fuses, before and after, then dimmer terminals 1, 2, and 4. If you can give me those, I bet I can tell you where the problem is.

Did the HIGH's work after you disabled DRL's? ...as in, are you absolutely sure?

 

[Stuntmonkey]

100% positive the highbeams aren't working after the DRLs were unplugged.

I've got to head off to work (14, 10hour days, REALLY suck), so I'll update this tomorrow when I get up and trace this back from the bulb.

Thanks again.

 

[TheDurk]

100% positive the highbeams aren't working after the DRLs were unplugged.

I've got to head off to work (14, 10hour days, REALLY suck), so I'll update this tomorrow when I get up and trace this back from the bulb.

Thanks again.

That wasn't the question. But looking at what you wrote, if they never worked after the disable, I'm thinking you may have used the wrong technique to disable DRL's. Each year, '00, '01, and '02 is different. Which year are you and how did you do the disable?

Meanwhile, if it is just a plug you pulled, why don't you re-enable and see what that does? Because the DRL's are definitely part of the HIGH circuit loop.

 

[Stuntmonkey]

1997. Disabled by unplugging module behind drivers side headlight. I've done it before and high beams worked fine. I only unplugged it just before my last post.

Plugged it in again and symptoms are the same.

 

[Stuntmonkey]

Just drove home, DRLs unplugged. Highbeams worked. I also didn't realize that the handbrake indicator light or seatbelt lights weren't coming on. And now everything is working.

Has to be a dirty common ground.